A new model of surface and underground integrated three-dimensional prevention and control of rock burst in Binchang Mining Area

With the continuous increase of coal mining intensity, the mine gradually moves to the deep, bringing about increasingly serious rock burst hazard. The deep rock burst mines often have one or more layers of hard and thick rock strata. These hard roofs are thick and strong integrity. When they suddenly rupture, they can release a large amount of elastic energies, which can easily to cause rock burst accidents and seriously restrict the safety of mine production. Herein, appropriate treatment measures were put forward for the special situation of deep burial depth of coal seam and general presence of many kinds of hard and thick rock strata in Mengcun Coal Mine in Binchang Mining Area, Shaanxi Province. These measure include: (1) Breaking and weakening treatment should be provided for the hard and thick rock strata with a thickness over 10 m within the range of 0‒80 m above the roof. (2) The roof deep-hole pre-split blasting measure should be taken for the low-level rock strata within the range of 0‒30 m above the coal seam. (3) The roof directional long-borehole hydraulic fracturing should be conducted to the middle-level hard rock strata within the range of 30‒60 m above the coal seam, and the staged fracturing of surface horizontal well should be performed for the high-level hard rock strata over 60 m above the coal seam. In this way, the fractures generated in the high, middle and low-level roof can be penetrated vertically, and thus the roof can be “cut” into a relatively regular “block” structure, so that the stress in the overlying strata can be transformed from “hard transmission” to “soft transmission”. Meanwhile, combined with the coal seam pressure relief measures such as large-diameter pressure relief and coal seam blasting, a surface and underground integrated three-dimensional prevention and control mode is formed, which integrates the regional and local areas, having the coal seam and rock stratum fully covered. The engineering practice has proved that: after the implementation of the 3D prevention and control mode, the microseismic events above 10³ J in the regional working face are reduced by 88%, the periodic weighting intensity is reduced by 23%, the weighting duration is shortened by 61%, and the anti-scour effect is good. Generally, the successful application of this technical model could provide a reference for the treatment of rock burst mine disasters under similar geological conditions.